A pendulous accelerometer is intended to measure the acceleration it sustains in a direction perpendicular to its principal plane. It commonly comprises a flat electrode formed in a Silicon on Isolator (or SOI) wafer and able to perform a rotary movement around an axis included in its plane (then referred to as a “pendulous” electrode), two counter-electrodes facing the pendulous electrode and forming with it two capacitances varying as a function of the angle of rotation of the pendulous electrode, the whole unit being encapsulated under an airtight cover and put under reduced pressure. An accelerometer of such a type is described for example in the document U.S. Pat. No. 5,905,203.
Hitherto the counter electrodes have been placed under the pendulous electrode and the electrical connections to the electrode and to the counter electrodes have been implemented in the SOI wafer. This involves in particular having a complicated layout of electrical connections in the SOI wafer, with the latter consequently occupying a significant amount of space, and using materials for the counter electrodes that are compatible with that of the SOI wafer, with these consequently being non-metallic materials.
Just like the previously described pendulous accelerometer, a pendulous gyrometer also comprises a mobile pendulous electrode associated with counter electrodes formed in an SOI wafer, and therefore offers identical drawbacks.